Towards the end of last year Lisa Rodrigues, a longstanding chief executive of a large NHS mental health trust, was driving home from work when something harrowing happened. "I was getting some terrible stomach pains. I couldn't see properly. I wanted to crash my car. I really had to [try hard to] stop myself doing that." She made it home safely but says she "cried for three days and three nights".

Rodrigues was in the midst of the first serious episode of clinical depression she had experienced in almost two decades but it was especially significant, she says, because the crisis point occurred weeks after she had made the decision to "come out" about her history of mental health problems.

That someone in such a senior management position in any organisation decides to talk openly about living with depression is rare and Rodrigues, 58, whose most trying times were in her teens and early 20s, acknowledges that speaking out was difficult. As she talks about her work and career, the last 13 years of which have been as chief executive of Sussex Partnership Foundation Trust, a provider of mental health, substance misuse, learning disability and prison healthcare services, she exudes the fervour of someone determined to bring her own experiences to bear.

She says, as retirement approached, she realised that talking about being in a demanding, senior position with a history of depression could have value. "I was just about to leave the NHS and that I wanted to talk about the fact that being a leader doesn't mean to say that you have to be perfect," she says.

The idea that living with a mental illness would exclude someone from a job they were capable of doing needs to be challenged, she suggests. "My experience of learning to manage my own emotions and deal with what I've just dealt with – I think I'm a better person for it without a doubt," she adds.

Reactions to her coming out were mostly encouraging, but some people commented that she "was the very last person" they would have expected to have mental health problems, or remarked, "You're not on antidepressants are you?" as if there was something wrong with it.

"There's this whole pill shaming thing that goes on", she says of the stigma attached to taking medication for a mental illness. "If you've got cancer and you come forward for treatment nobody judges you. To be frank I would be dead if I hadn't taken antidepressants because I was so low."

She argues that, despite some progress in recent years, it is stigma across society that is a primary cause of negative attitudes and also affects behaviour and the way mental health services are funded and organised.

"Why is it that mental health services in this country only get 12% of the resources that we have available, given that it is at least 25% of the disease burden? I think we start with the stigma," she argues. "If we can start by talking about the stigma … that means people are more likely to invest in services to help those people have a better life."

Her analysis of the mental healthcare system is measured and illuminating. It is clear she has relished the difficult task of running a complex health trust in a time of immense change, and believes she has helped improve some aspects of healthcare, including advocating for more integration between mental and physical provision, in particular for older people.

The impact of the economic downturn and benefits changes have been "quite significant", Rodrigues says, because the most vulnerable people are under enormous pressure. "We've got the benefit changes affecting patients and so too the increase in prices for things and also the changes in housing benefit. So they've got a triple whammy. When we are seeing them they're more ill and tend to stay in hospital longer."

In other areas cuts to funding coupled with changes to the commissioning of child and adolescent mental healthcare are especially problematic, she suggests, because "early intervention" is so vital to longer term mental wellbeing and to reducing the demands on "other parts of the system" such as A&E and the criminal justice system further down the line. The past year has seen a "serious" jump of 10% nationally in the number of young people accessing services, yet there are "no hospital beds for children and young people anywhere in the country at any one time" to accommodate those in crisis.

While still evidently passionate about how the health system operates, there is a sense that Rodrigues is steadily coming to terms with moving on and segueing into the role of campaigner. "For the next third of my life I will be campaigning about this stuff," she replies. "I don't want to be running it. I want to write about it. I want to shout about it because I think I can make quite a difference."

But what makes her think people will listen to what she has to say? "I will make sure they do. I'm quite hard to say no to," she asserts with a smile.

Curriculum vitae

Age 58.

Lives Brighton, east Sussex.

Family Married, two grown-up children.

Education Horsham high school for Girls, West Sussex, Dunottar school, Reigate, Surrey; University of Sussex, BA in psychology, BA and MA, public sector management.